80’s Smartwatch Finally Plays Tetris

While the current generation of smartwatches have only been on the market for a few years, companies have been trying to put a computer on your wrist since as far back as the 80s with varying degrees of success. One such company was Seiko, who in 1984 unveiled the UC-2000: a delightfully antiquated attempt at bridging the gap between wristwatch and personal computer. Featuring a 4-bit CPU, 2 KB of RAM, and 6 KB of ROM, the UC-2000 was closer to a Tamagotchi than its modern day counterparts, but at least it could run BASIC.

Dumping registers

Ever since he saw the UC-2000 mentioned online, [Alexander] wanted to get one and try his hand at developing his own software for it. After securing one on eBay, the first challenge was getting it connected up to a modern computer. (Translated from Russian here.) [Alexander] managed to modernize the UC-2000’s novel induction based data transfer mechanism with help from a ATtiny85, which allowed him to get his own code on the watch, all that was left was figuring out how to write it.

With extremely limited published information, and no toolchain, [Alexander] did an incredible job of figuring out the assembly required to interact with the hardware. Along the way he made a number of discoveries which set his plans back, such as the fact that there is no way to directly control individual pixels on the screen; all graphics would have to be done with the built-in symbols.

The culmination of all this hard work? Playing Tetris, naturally. Though [Alexander] admits that limitations of the device’s hardware meant the game had to be simplified a bit, he’s almost certainly having more fun than any of the UC-2000’s original owners did with this device. He’s setup a GitHub repository for anyone who wishes to join him in this brave new world of vintage wrist computing.

[Alexander] isn’t the only one experimenting with fringe wearable computers. We’ve seen our fair share of interesting smartwatches, featuring everything from novel input methods to complete scratch-builds.

Continue reading “80’s Smartwatch Finally Plays Tetris”

Keeping Time with a Spring Powered Integrated Circuit

Watch aficionados have a certain lust for mechanical watches. These old school designs rely on a spring that’s wound up to store energy. The movement, an intricate set of gears and other mechanical bits, ensures that the hands on the watch face rotates at the right speed. They can be considered major feats of mechanical engineering, with hundreds of pieces in an enclosure that fits on the wrist. They’re quite cheap, and you have to pay a lot for accuracy.

Quartz watches are what you usually see nowadays. They use a quartz crystal oscillator, usually running at 32.768 kHz. These watches are powered by batteries, and beat out their mechanical counterparts for accuracy. They’re also extremely cheap.

Back in 1977, a watchmaker at Seiko set off to make a mechanical watch regulated by a quartz crystal. This watch would be the best of both words. It did not become a reality until 1997, when Seiko launched the Spring Drive Movement.

A Blog To Watch goes through the design and history of the Spring Drive movement. Essentially, it uses a super low power integrated circuit, which consumes only 25 nanowatts. This IC receives power from the wound up spring, and controls an electromagnetic brake which allows the movement to be timed precisely. The writeup gives a full explanation of how the watch works, then goes through the 30 year progression from idea to product.

Once you’ve wrapped your head around that particularly awesome piece of engineering, you might want to jump into the details that make those quartz crystal resonators so useful.

[Thanks to John K. for the tip!]